For one Mana, Ruin Crab is a Blue 0/3, hooray
The Minstrels Ballad At the beginning of combat on your turn, if you control five or more Towns, create a 2/2 Elemental creature token thats all colors
Questing Beast If Elder Gargaroth is a planeswalker on a creature, this is a planeswalker assassin
Once you get to 12 counters, these planets become some of the most powerful lands in the game (Tolarian Academy, Gaea's Cradle)
Lion Sash is one of the better ones for its affordable mana value and ability to mimic Scavenging Ooze and the instant-speed shenanigans it enables, all at a low Reconfigure cost
Pair it with some artifact cost reducers and cards like Sai, Master Thopterist that reward you for casting artifacts each turn, and this could work as a low-power value engine